AKN-028 induces cell cycle arrest, downregulation of Myc associated genes and dose dependent reduction of tyrosine kinase activity in acute myeloid leukemia

Abstract The c-Myc multifunctional transcription factor protein, a product on the c-myc proto-oncogene, contributes to the pathogenesis of many types of human cancers through mechanisms of proliferation, apoptosis, cell cycle progression and cellular senescence. c-Myc is frequently overexpressed in acute myeloid leukemia, yet strategies to effectively modulate c-Myc function do not exist. We evaluated inhibition of c-myc gene expression by APTO-253, a small molecule anticancer agent that is being developed clinically for the treatment of acute myelogenous (myeloid) leukemia (AML) and high risk myelodysplastic syndromes (MDS). We first confirmed that c-Myc mRNA level were significantly higher in AML cell lines as compared to peripheral blood mononuclear cells (PBMCs) isolated from healthy human donors. However, the c-Myc expression in AML cells was inhibited by APTO-253 in dose-dependent and time-dependent manners at both the mRNA and protein levels. Likewise, APTO-253 was found to induce AML cell apoptosis in dose-dependent and time-dependent manners as demonstrated by positive Annexin-V staining and increases in cleaved poly (ADP-ribose) polymerase (c-PARP). APTO-253 induced AML cells arrest at G1/G0 phase of cell cycle by increasing p21 expression and decreasing expression of cyclin D3 and cyclin-dependent kinases 4/6 (CDK4/6). For the p53 positive cell lines MV4-11 and EOL-1, p53 was also increased by APTO-253 at early time points (less than 6-hour treatment), suggesting that p53-dependent cell cycle arrest and apoptosis is mechanistically operative as a consequence of treatment with APTO-253. Importantly, we demonstrated that APTO-253 selectively targeted tumor cells but not normal healthy cells, with MV4-11 AML cells and normal PBMCs having IC50s of 0.25±0.03µM and more than 100µM, respectively. Our previous studies (56th ASH abstract #4813) showed that APTO-253 induces the Krüppel-like Factor 4 (KLF4) transcription factor and was effective and well tolerated as a single agent in multiple AML xenograft models without causing bone marrow suppression. Taken together, our results suggested that APTO-253 may serve as an effective and safe agent for AML chemotherapy, and that APTO-253 mechanistically inhibits c-Myc expression in AML cells and subsequently induces cell cycle arrest and apoptosis. Disclosures No relevant conflicts of interest to declare.

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Octadecyloxyethyl Adefovir Exhibits Potent in vitro and in vivo Cytotoxic Activity and Has Synergistic Effects with Ara-C in Acute Myeloid Leukemia

Chemotherapy ◽

10.1159/000491705 ◽

2018 ◽

Vol 63 (4) ◽

pp. 225-237 ◽

Cited By ~ 1

Author(s):

Haytham Khoury ◽

Ruijuan He ◽

Aaron Schimmer ◽

James R. Beadle ◽

Karl Y. Hostetler ◽

...

Keyword(s):

Cell Cycle ◽

Dna Damage ◽

Acute Myeloid Leukemia ◽

Cell Cycle Arrest ◽

Clinical Benefit ◽

Myeloid Leukemia ◽

Mouse Bone Marrow ◽

Medical Needs ◽

Cycle Arrest ◽

Acute Myeloid

Acute myeloid leukemia (AML) continues to be a deadly disease, with only 50–70% of patients achieving complete remission and less than 30% of adults having sustained long-term remissions. In order to address these unmet medical needs, we carried out a high-throughput screen of an in-house library of on- and off-patent drugs with the OCI/AML-2 cell line. Through this screen, we discovered adefovir dipivoxil (adefovir-DP) as being active against human AML. In addition to adefovir-DP, there are second-generation formulations of adefovir, including octadecyloxyethyl adefovir (ODE-adefovir) and hexadecyloxypropyl adefovir (HDP-adefovir), which were designed to overcome the pharmacokinetic problems of the parent compound adefovir. Given the known clinical benefit of nucleoside analogs for the treatment of AML, we undertook studies to evaluate the potential benefit of adefovir-based molecules. In AML cell lines and patient samples, adefovir-DP and ODE-adefovir were highly potent, whereas HDP-adefovir was significantly less active. Interestingly, ODE-adefovir was remarkably less toxic than adefovir-DP towards normal hematopoietic cells. In addition, ODE-adefovir at a dose of 15 mg/kg/day showed potent activity against human AML in a NOD/SCID mouse model, with a reduction of human leukemia in mouse bone marrow of > 40% in all mice tested within 20 days of treatment. Based on its chemical structure, we hypothesized that the cytotoxicity of ODE-adefovir toward AML was through cell cycle arrest and DNA damage. Indeed, ODE-adefovir treatment induced cell cycle arrest in the S phase and increased levels of pH2Ax, indicating the induction of DNA damage. Furthermore, there was an increase in phospho-p53, transactivation of proapoptotic genes and activation of the intrinsic apoptotic pathway. Subsequent investigation unveiled strong synergism between ODE-adefovir and ara-C, making their coadministration of potential clinical benefit. Expression of MRP4, a nucleoside transporter, appeared to influence the response of AML cells to ODE-adefovir, as its inhibition potentiated ODE-adefovir killing. Taken together, our findings indicate that clinical development of ODE-adefovir or related compounds for the treatment of AML is warranted.

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Axolotl Ambystoma mexicanum extract induces cell cycle arrest and differentiation in human acute myeloid leukemia HL-60 cells

Tumor Biology ◽

10.1177/1010428320954735 ◽

2020 ◽

Vol 42 (9) ◽

pp. 101042832095473

Author(s):

Sherif Suleiman ◽

Riccardo Di Fiore ◽

Analisse Cassar ◽

Melissa Marie Formosa ◽

Pierre Schembri-Wismayer ◽

...

Keyword(s):

Cell Cycle ◽

Acute Myeloid Leukemia ◽

Anticancer Activity ◽

Cell Cycle Arrest ◽

Crude Extract ◽

Myeloid Leukemia ◽

Ambystoma Mexicanum ◽

Cycle Arrest ◽

Human Acute Myeloid Leukemia ◽

Acute Myeloid

Acute myeloid leukemia is the most common form of acute leukemia in adults, constituting about 80% of cases. Although remarkable progress has been made in the therapeutic scenario for patients with acute myeloid leukemia, research and development of new and effective anticancer agents to improve patient outcome and minimize toxicity is needed. In this study, the antitumor activity of axolotl (AXO) Ambystoma mexicanum crude extract was assessed in vitro on the human acute myeloid leukemia HL-60 cell line. The anticancer activity was evaluated in terms of ability to influence proliferative activity, cell viability, cell cycle arrest, and differentiation. Moreover, gene expression analysis was performed to evaluate the genes involved in the regulation of these processes. The AXO crude extract exhibited antiproliferative but not cytotoxic activities on HL-60 cells, with cell cycle arrest in the G0/G1 phase. Furthermore, the AXO-treated HL-60 cells showed an increase in both the percentage of nitroblue tetrazolium positive cells and the expression of CD11b, whereas the proportion of CD14-positive cells did not change, suggesting that extract is able to induce differentiation toward the granulocytic lineage. Finally, the treatment with AXO extract caused upregulation of CEBPA, CEBPB, CEBPE, SPI1, CDKN1A, and CDKN2C, and downregulation of c-MYC. Our data clearly show the potential anticancer activity of Ambystoma mexicanum on HL-60 cells and suggest that it could help develop promising therapeutic agents for the treatment of acute myeloid leukemia.

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Abstract 4678: The role of EGR1 and AP1 in acute myeloid leukemia cell reprogramming toward cell cycle arrest and apoptosis

10.1158/1538-7445.am2020-4678 ◽

2020 ◽

Author(s):

Michael Roberts ◽

Lauren Kageler ◽

Kayla Bendinelli ◽

Shannon Bonner ◽

Ashir Borah ◽

...

Keyword(s):

Cell Cycle ◽

Acute Myeloid Leukemia ◽

Cell Cycle Arrest ◽

Myeloid Leukemia ◽

Leukemia Cell ◽

Cell Reprogramming ◽

Cycle Arrest ◽

Acute Myeloid ◽

Myeloid Leukemia Cell

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G1 Cell-Cycle Arrest and Apoptosis by Histone Deacetylase Inhibition in MLL-AF9 Acute Myeloid Leukemia Cells Is MLL-AF9 Independent.

Blood ◽

10.1182/blood.v106.11.4410.4410 ◽

2005 ◽

Vol 106 (11) ◽

pp. 4410-4410

Author(s):

Roberto Tonelli ◽

Roberta Sartini ◽

Raffaele Fronza ◽

Francesca Freccero ◽

Monica Franzoni ◽

...

Keyword(s):

Cell Cycle ◽

Acute Myeloid Leukemia ◽

Cell Growth ◽

Cell Cycle Arrest ◽

Myeloid Leukemia ◽

Combined Treatment ◽

Histone Deacetylase Inhibition ◽

Cycle Arrest ◽

G1 Cell Cycle Arrest ◽

Acute Myeloid

Abstract Acute myeloid leukemia (AML) with MLL rearrangements (MLLmut), found mainly in M5 or M4 FAB subtypes, is frequent in infants and secondary leukemias. The most common MLL translocation gives rise to MLL-AF9. MLL protein interacts with histone deacetylases (HDACs) -1 and -2 through the MLL repression domain. We report the effects of HDAC inhibition by valproic acid (VPA) in MLL-AF9 AML-M5 cells (THP-1, MM6 and MOLM-13) and MLLmut AML-M5 blasts. VPA led to histone hyper-acetylation, strong cell-growth inhibition, G1 cell-cycle arrest and apoptosis. Combined treatment with all-trans-retinoic-acid (ATRA) did not substantially improve these effects. VPA increased MLL-AF9 transcription, indicating that VPA overcomes the cell-growth promoting activity and resistance to apoptosis conferred by MLL-AF9 in AML-M5 cells, even with increased MLL-AF9. A small number of genes were significantly affected by VPA in p53-absent THP-1 cells (GeneChip analysis), and the majority of these were up-regulated. VPA potently induced p21 and cyclin G2 (CG2) expression. p21 and CG2 targeted inhibition demonstrated that p21 acts as a key regulator in the VPA-inducted G1 cell-cycle arrest, while induction of CG2 has no effect. These data suggest that these poor prognosis patients may benefit from HDAC inhibitor therapy.

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